Computer networking began proliferating when the data transfer rates of industry standard architectures could not keep pace with the data access rate of the 80386 processor made by Intel Corporation. Local area networks (LANs) evolved to storage area networks (SANs) by consolidating the data storage capacity in the network. Users have realized significant benefits by the consolidation of equipment and the associated data handled by the equipment in SANs, such as the capability of handling an order of magnitude more storage than would otherwise be possible with direct attached storage, and doing so at manageable costs.
More recently the movement has been toward a network-centric approach to controlling the data storage subsystems. That is, in the same way that the storage was consolidated, so too are the systems that control the functionality of the storage being offloaded from the servers and into the network itself. Host-based software, for example, can delegate maintenance and management tasks to intelligent switches or to a specialized network storage services platform. Appliance-based solutions eliminate the need for the software running in the hosts, and operate within computers placed as a node in the enterprise. In any event, the intelligent network solutions can centralize such things as storage allocation routines, backup routines, and fault tolerance schemes independently of the hosts.
While moving the intelligence from the hosts to the network resolves some problems such as these, it does not resolve the inherent difficulties associated with the general lack of flexibility in altering the presentation of virtual storage to the hosts. For example, data stored under the auspices of one controller might be more efficiently accessed in the storage space of a different controller. In this event either the host or the network must first copy the data in order to make it available to the other controller. What is needed is an intelligent data storage subsystem that self-deterministically allocates, manages, and protects its respective data storage capacity and presents that capacity as a virtual storage space to the network to optimize I/O performance system wide. This virtual storage space is able to be provisioned into multiple storage volumes. A distributed computing environment uses these intelligent storage elements to share the load of processing I/O commands as evenly as possible throughout the storage array. It is to this solution that embodiments of the present invention are directed.